From the description: "The sword is 2-handed when you find it, but if your expertise lies with 1-handed, no problem. You can take the Infinity Sword to a smelter and switch it into a 1-handed sword without needing any ingots, materials or perks to do so. "

in your picturs its shows your charictor hodling it with one hand. but in your notes you say its a greatsword which if im mistaken are used with 2 hands not 1. so if it is a onehanded wepon then please tell us that

Lost to the Ages can be started at any time, though the recommended level is 16. It's started by reading the book The Aetherium Wars, which is found hither and yon. One guaranteed spot is the HQ of the Vigilant of Stendarr

It shouldn't, it uses its own script for launching projectiles, it just uses modified meshes of the Bloodskal Blade's projectiles. Script lag or congestion could be affecting the Blooskal Blade's effect, or it got screwed up some other way. You can try dropping the sword, then picking it back up after a moment or two and see if that helps. If not, making a new save, quitting then reloading might help.

Using the power attack effects are a tactical choice, really. If you've got friendlies nearby along with baddies, it's best to refrain from using the power attacks so you don't nuke everybody. If I'm not mistaken though they won't harm followers. I may sometime make it that the blasts won't harm people who aren't hostile to you, but until then it's best to be cautious, especially in cities.

Right ~now~, no, but overall it is. It's labeled as a WIP not because I'm always working on it but because it's not technically complete. It's usable, yes, perfectly so, but there's stuff that I hope to add (like a questline and other bits and bobs) before I'd consider it complete.

Skyrim Sorcery could have popped it out of the rock it's stuck into within the lava field. Its rock is the farthest out, close to a little spot of land where a dwarven chest chills out. Best thing to do would be to use the TFC command to fly around the lava lake to pin down where it ended up. Also make sure the mod's active by checking the Data Files section of the launcher.

Script delay is the most likely cause. If it's bad enough the effect won't happen at all because, I suspect, the Papyrus engine is already processing so much, so it drops the script. Be sure, though, that you're not suffering from a script FREEZE. You know when this has happened if certain things just stop working, like the push effect on Unrelenting Force, or absorbing dragon souls. In that case, saving, quitting and reloading is usually enough to kick-start the script engine and free whatever got clogged in the works.